1. Field of the Invention
The present invention relates to a method of creating a sample page, a program, and an image forming system.
2. Description of the Related Art
In the printing field, there are colors that require accurate color reproducibility, such as a corporate color used for a logo of a company. Such a color is reproduced by using a specially mixed dedicated ink in offset printing (hereinafter, the color is referred to as “special color (spot color)”).
Meanwhile, in the printing market where image forming devices in an offset printing system are often used, a case of using an image forming device in an electrophotographic system or an image forming device in an ink jet system has been increasing.
In the image forming device in an electrophotographic system, printing is performed using a dedicated library (spot color library) in which reproduction of the special color is approximated by a combination of toners of C, M, Y, and K basic colors (for example, JP 2010-278494 A).
Further, the image forming device in an electrophotographic system reproduces the special color with the combination of the toners of the basic colors as described above, output results vary due to various causes such as a difference between the devices or a variation of change of the devices. Therefore, patch images generated with different amounts of toners with different signal strengths are formed, the density and the color information are manually measured, and the patch images are visually compared with a color guide, so that C, M, Y, and K values (printer device values) of the spot color library are edited, and color adjustment is performed.
Stability of the color reproduction is important and is strictly managed with respect to the special color. In variable printing in which mass printing is performed, there is a problem that the color is being changed as a large number of sheets of printing is performed, even if the color adjustment is performed before the mass printing is started. In such a case, when a change amount exceeds a threshold, readjustment of the special color is performed.
At this time, the color adjustment may be performed by referring to a past output and taking the past output as a landmark. However, there is a problem that, to use the past output, extraction of a printed portion of the special color from the mass printed sheets is required, and a lot of labor is required to perform determination related to the readjustment and the determination is not so easy.
Further, in the printing market, handling of a wide variety of sheets is required, and handling of not only white papers but also papers with a color (colored papers) is required.
Between a case of using a white paper and a case of using a colored paper other than white, even if the same special color is output, the colors (color measurement values) are changed due to influence of a background paper. Further, due to an illusion, even if images having the same color measurement value are formed, the images may sometimes be viewed with different colors due to the difference of the background colors. For example, it is known that a color arranged in a dark background color is recognized brighter than a color arranged in a bright background color due to an illusion, and when the background color is vivid yellow, a color arranged in the yellow is seen as a bluish color that is at a complementary color side of the background color, due to an illusion.
JP 2012-228836 A discloses that, in a printing device in an ink jet system, a color chart is printed, the color chart being formed such that a plurality of blocks made of a plurality of color patches is arranged in a main scanning direction, then a colorimeter is temporarily attached to the printing device and color measurement is performed, and then a color difference (ΔE) between a color measurement result of each block and a block serving as a reference, and a color difference between the color measurement result of each block and a past output result are printed in the vicinity of each color patch.
Although the printing device described in JP 2012-228836 A can compare the color differences, the printing device cannot visually compare an actual image with the past color as to how the actual image is changed from the past color, with respect to the special color that requires strict management.
Further, the printing device described in JP 2012-228836 A cannot confirm an actual output, with respect to the special color that requires strict management.
Further, when managing the special color, there is a case of desiring confirmation of the output image of the special color or color adjustment of the special color in consideration of the influence of the difference of the colors of the background sheets.